Lenses, for glasses, telescopes, optical microscopes, or cameras, for example, are quite common optical components. Transmission (e.g., often expressed as a ratio of transmission/non-transmission or a ratio of transmission/total available light) of light, especially within specific light wavelengths, is an important index for evaluating the optical characteristics of a lens.
Typically, transmission of a lens is measured using the following method: a light source is positioned on one side of a lens to be tested and a photo multiplier tube (PMT) is positioned on the other side of the lens. When the light source emits light onto the lens, part of the light is transmitted through the lens (with another portion lost to, e.g., reflection and/or attenuation) and is detected by the photo multiplier tube. Transmission of the lens is calculated by comparing the intensity of light incident on the lens with the intensity of light transmitted from the lens. However, the detection rate of the photo multiplier tube is relatively slow, and, as a result, is generally not suitable for testing of lenses in mass production. Therefore, it is desired to develop a rapid testing apparatus for testing of light transmission through lenses.